A quick review of z-scores and how to understand them August 26, 2011

Similar presentations

Presentation on theme: "A quick review of z-scores and how to understand them August 26, 2011"— Presentation transcript:

1 A quick review of z-scores and how to understand them August 26, 2011What is a Z-Score?A quick review of z-scores and how to understand themAugust 26, 2011

2 Z-Score “Cheat Sheet”Z-scores are a standardized measure that helps you compare individual student (or school) data to state average data.Student z-score =(Student Scale Score) – (Statewide average of scale scores)Standard Deviation of Scale ScoreSchool z-score=(School Value) – (Statewide average of that value)Standard deviation of that value

3 Z-Score “Cheat Sheet” Z-scores are centered around zeroPositive numbers mean the student or school is above the state averageNegative numbers mean the student or school is below the state averageStateAverage…Worse than state averageBetter than state average….-3-2-1123

4 Z-Score ExamplesYour school has a z-score of You are better than the state average.Z-score of 1.5StateAverage…Worse than state averageBetter than state average….-3-2-1123

5 Z-Score ExamplesYour school has a z-score of .2. You are better than the state average, but not by a lot.Z-score of 0.2Z-score of 1.5StateAverage…Worse than state averageBetter than state average….-3-2-1123

6 Z-Score ExamplesYour school has a z-score of You are very far below state average.Z-score of -2.0Z-score of 0.2Z-score of 1.5StateAverage…Worse than state averageBetter than state average….-3-2-1123